Various methods and apparatus have been described for modifying a surface of a body using electromagnetic radiation. Thus, for example, European Patent Application EP-A-137701, British Patent application GB-A-2119268 and GB-A-2130009 describe various methods of annealing or crystallising material using an electromagnetic radiation source such as a laser. In particular, EP-A-137701 (Fujitsu) describes annealing to ensure silicidation of a refractory metal barrier provided between a silicon surface and an aluminium silicide layer. The British Patent Application GB-A-2119168 describes a method of forming a crystalline semiconductor layer by depositing polycrystalline silicon in a rectangular opening in insulating material onto a monocrystalline silicon substrate, and then annealing the polycrystalline silicon with a CW Ar laser beam to cause recrystallisation while GB-A-2130009 (RCA) describes the thermal annealing of amorphous silicon to produce polycrystalline silicon films.
The use of electromagnetic radiation to modify the surface of a body by radiantly heating the surface during growth of material, for example semiconductor material, on the surface is described in, for example, British Patent Application GB-A-1515571 and GB-A-2170043 while the technique of using electromagnetic radiation to cause dissociation of gaseous material to enable growth of material on the surface is described in, for example, a paper presented at the Internation Symposium on GaAs and related compounds, Karuizawa, Japan 1985 and published under the title "Future epitaxial growth process : Photo-MOMBE" by Kiyoshi Takahashi in the Inst. Phys. Conf. Ser. No 79 Chapter 2 at pages 73 to 78.